Fabrication and test of sol-gel based planar oxygen optodes for use in aquatic sediments

B Konig, O Kohls, G Holst, Ronnie Glud, M Kuhl

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Abstract

We describe the fabrication of organically modified sol-gel (ORMOSIL) planar optodes for mapping the two-dimensional oxygen distribution in sediments. All sensor foils were based on the use of ruthenium(II)-tris-(4,7-diphenyl-1,10-phenantrolin)perchlorate, which is a fluorescent dye quenched dynamically by oxygen. Sensors made with different sol-gel immobilisation matrices, different concentrations of precursors and indicator dye, as well as different types of scattering particles co-immobilised in the sensor foil were investigated systematically. Optimal sensor performance was obtained with dye concentrations of 2-10 mmol/kg in an immobilisation matrix made of diphenyldiethoxy-silan and phenyltriethoxy-silan precursors with addition of organically coated TiO2 particles. The sensors exhibited a good mechanical stability and a high sensitivity from 0% to 100% oxygen, which remained constant over at least 36 days. The planar optodes were used with a fluorescent lifetime imaging system for direct mapping of the spatio-temporal variation in oxygen distribution within marine sediment inhabited by the polychaete Hediste diversicolor. The measurements demonstrated the spatio-temporal heterogeneity of the oxygen distribution in bioturbated sediments due to burrow structures and non-constant irrigation activity of the polychaete, which is difficult to resolve with microsensors or with traditional biogeochemical techniques. (c) 2005 Elsevier B.V All rights reserved.
Original languageEnglish
Pages (from-to)262-276
Number of pages15
JournalMAR CHEM
Volume97
Issue number3-4
DOIs
Publication statusPublished - 2005

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Keywords

  • O-2
  • Chemistry, Multidisciplinary
  • SEA
  • LIFETIME IMAGING-SYSTEM
  • COATINGS
  • Oceanography
  • MARINE-SEDIMENTS
  • MICRO-OPTODES
  • FLUORESCENCE
  • BIOLOGICAL SAMPLES
  • LUMINESCENCE QUENCHING BEHAVIOR
  • RU(II) COMPLEX

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